﻿using System;

class Program
{
    static void Main()
    {
        Shape[] shapes =
        {
            new Triangle(5,5),
            new Triangle(9,9),
            new Rectangle(5,5),
            new Rectangle(9,9),
            new Circle(5),
            new Circle(9),

        };
        foreach (var shape in shapes)
        {
            Console.WriteLine(shape.CalculateSurface());
        }
    }
}